Soccer - played by 250 million people across 200 countries - is the most popular sport on earth.

It evokes great passion and plays an important role in the lives of fans, local communities and even nations.

But it's also transforming lives much closer to home.

This weekend the annual national street soccer championships will be held, staged on a purpose-built, floating pitch at Darling Harbour.

It's an initiative of The Big Issue - which runs a national street soccer program for the homeless, jobless and disadvantaged.

About 600 people play each week in NSW - in Sydney, Parramatta, Wollongong and Newcastle.

702 Breakfast host Adam Spencer took part in a pre-tournament match, in the lead up to this weekend's tournament.

"I love football, I love The Big Issue and I have played on this floating platform at Darling Harbour before," Spencer says.

"When you are standing still here, I feel like I could vomit.

"But when you are running around out there, you don't notice it, but the great thing is if you really make an air swing you can blame it on oh the pitch, the conditions."

You can listen to more of what Adam Spencer had to say about the tournament on this page.

David Middleton has been the coach of Sydney's team for more than two years and says street soccer is much faster than a normal game because it's played on an enclosed pitch and uses four players a side.

"It's a lot faster game. You need to be very fit and really switched on because it is just so fast," he says.

He says that winning is great, but the most satisfying part of his role is seeing the sport transforming lives.

One example is goalie Adam Connell who joined the team after watching the tournament 18 months ago.

"He's an extremely good goal keeper and his confidence has just blossomed," Middleton says.

"He's got some work now, whereas before he was just living on the streets.

"From being really shy to start with, he's really come out of his shell."

Adam Connell says joining the team has been life-transforming, because he now feels part of a community.

"It's given me someone to talk to. It's gotten me off the streets, and it's gotten a fair few other people off the streets as well."

The tournament will be held on the floating pitch in front of the Convention Centre at Darling Harbour on Saturday and Sunday afternoon.

You can find out more information about The Big Issue Community Street Soccer Program here.

Listen to a report on the event on this page.

Update: Sadly NSW didn't win. The South Australian team was victorious on the day. NSW finished in sixth place.